MCZ Musa Hydro 15kw - thoughts

Now don't go scare mongering again, the deaths from wood pellet storage have been when an unprepared operative has been in a pellet bunker where several tons of pellets have been stored for a length of time and have been allowed to degrade, thus producing CO2.
We store our pellets in a sealed room in our house, half a ton at a time, with a carbon monoxide detector right next to them, it has never gone off.

Anyway, I have some very sorry news to relate to you all.....

OUR MUSA HYDRO 22 BLEW UP LAST WEDNESDAY!!!

As you know I have defended the maker on these boards, believing what my installer had been told by the UK inspection agency -Specflue, ie that the problems were caused by poor installation and servicing.
I can tell you that our installer did a good job, and I cleaned and serviced the boiler frequently, and yet last Wednesday morning it blew up showering shards of hot glass across our kitchen floor. Only minutes earlier my wife had been warming herself by the boiler, thank God our little boy was in nursery that day!
As if I wasn't angry enough that my family had been put in such danger, and after I had defended the manufacturer on these forums, only to have our boiler blow up in such a dangerous way, when the inspector from Specflue came the next day he did his damnest to divert the blame away from the boiler.
He criticised me for moving one of our CO detectors away from the boiler to a room with an old stove in it (far more likely to leak CO), he also criticised the installer for not putting a wall plate up detailing the boilers specifications. Neither of these items were even connected to the boiler, and could not cause it to malfunction.
Not once did he inspect the boiler that blew up, not once did he ask how the explosion happened (for those interested, it was not on warm up as you might expect, but when the boiler was warmed up and functioning normally), he was quite blatantly trying to find any reason to shift blame from the manufacturers. If it hadn't been so potentially tragic, it would have resembled a comedy sketch.
As expected, when his report arrived, it blamed the explosion on a poor installation.
It's like saying the engine in your car blew up because you had worn windscreen wipers!

Anyway, our installers were superb. Within a day they had the old boiler out, and replaced it temporarily with a Klover Diva Mid from their workshops. We were all up and running within 36 hours of the explosion, that is good service.
As far as I know there have been no problems with Klover, and we are thinking of staying with them if there are no further problems.

If you have a Musa Hydro, please, please get someone to inspect it.

For my twopenneth, I suspect there is a design flaw in the chamber above the firing chamber. The firing chamber is large and unobstructed, the 'riddling tubes' are cleaned by sliding the rods up and down daily, but the chamber between cannot be accessed except in the annual service, I think there may be a built up of soot/unburned fine particles there which can fall as a lump back into the firing chamber and initially put the flame out, but then reignite with the heat.
Just my theory, but as the inspector didn't inspect, it's as good a theory as any.
My wife said that there was a small thump/explosion sound followed by lots of soot/smoke coming out of the machine, then the glass exploded.
I feel let down by the manufacturer allowing such a machine to still be sold (is it cheaper to put up with the law suits than to recall the machines and refund I wonder), but more so by the inspector who's job it is to keep us all safe. Maybe someone should inspect he inspectors - Quis custodiet ipsos custodes?

Anyway, enough of my spleen venting, keep safe and get your boiler serviced regularly, whatever manufacturer or fuel type it is.

@Burnardo, thanks for posting the update about your boiler. It's fortunate that no-one was injured by the explosion. Your comments on the importer's response are very enlightening and put into context what has been written about rogue installers being responsible for the defective boilers.

It sounds like your installer's response has been excellent. Klover was our preferred boiler and there don't seem to be any reports of problems with this manufacturer online.

@Burnando sorry to hear about the demise of your MCZ boiler but the good news is that noone has been hurt. I think what has happened puts in to context my comments about a potential design flaw. Even if it relates to the flue installation MCZ and Specflue have a responsibility to make this clear in the installation instructions. The lack of action and the blaming of poor installation puts this on a par with Beko's response to product problems.

Thanks everyone for your concern, yes it could have been a lot worse than it was, we count ourselves lucky. And I allow myself a pat on the back for spending time researching our chosen installer, and paying more than the cheapest quote, we have certainly got our money's worth.

@Cancunia, the boiler was only installed last May, so it hadn't had an annual service, but I followed the cleaning and maintenance schedule religiously.
If by pressure relief valve you mean the flue stabiliser (flappy thing), we had one, and it worked perfectly.

When the machine was uninstalled, the flue was perfectly clear, in fact I took a photo of where the flue gasses left the machine as they entered the flue pipe, it was perfectly clear with just a fine light grey coating of dust as you might expect. The blockage/problem was much closer to the furnace hearth than the flue.

My installer has had a long conversation with the BRE over the installation, detailing exact measurements of air inlet pipe, exhaust flue diameter/length etc, it was installed as per (if not exceeding) correct specifications.

One thing I forgot to mention in my last post, my wife heard the inspector say, well almost mutter under his breath 'I'd have them all ripped out if I had my way'.
I'm sure he'd never put that on paper, but it sounds like they know there is a problem.

Well our Klover is working well, the house is lovely and warm, we have copious amounts of hot water, and last weeks trauma is fading in the memory.
I do like to think when I sink into a lovely hot bath that all the heat in the water and in the house is in reality distilled sunshine :T

Burnado, I'm really glad to hear that your problems are a fading memory and your family was not hurt in the incident - apart of course from the shock. If your boiler was only installed in May of this year, I can't see how it can be due to the flue blocking with soot.

I did some more looking on the German (Haustechnik) & Italian (stufapellet) forums and could only find 1 problem that seemed to match what we're seeing in the UK. The Italian one was from 2010 and seemed to say that there was a problem on a Nova Hydro due to pellets getting blocked / backed up in the delivery tube and then putting the flame out when a lot were delievered into the grate, somehow it suddenly caught and caused an explosion. It seems that the Nova had some kind of special vent in the case of explosions. I think this stove is now obselete and a lot of other safety measures were introduced via the 'Active' firmware.

However, I also talked with Specflue. While there were no details to hand, it was mentioned that the fix being tested is to introduce some kind of device into the actual boiler to take away the chance of the glass being the weakest point. They also confirmed that the only incidents so far have been on 22kw models. Unfortunately, there were no details about when this fix will be applied, only that it will be applied to all 22kw models at least, possibly 15kw models too.

Hopefully someone from Specflue will notice this ever growing thread and make some kind of comment about what they are doing & when.